The image on the left was obtained using a holography technique [Meng & Hussain, Appl. Opt. 34, 1827 (1995)] and display a
nonlinear breakdown of a drop into water. The drop, aqueous polystyrene suspension with 90% water and 0.5cm in diameter, falls
freely from a distance of 1cm above the water surface. The drop undergoes vortex ring instability that cascade on smaller and
smaller scales (droplets, wakelets, ringlets) and yield flow crowns, 3D arcades and chaotic structures.

The image on the right was taken
by J. J. Thompson and H. J. Newal (Proc. Roy. Soc. 39 in 1885, showing similar instabilities demonstrated by dye entering water.